ECOSCOPA network : National monitoring network of mortality and growth rates of the sentinel oyster Crassostrea gigas

the network was initiated by ifremer from 1993 to 2009 (under the acronym remora) to study the rearing performance of the pacific oyster crassostrea gigas at a national scale. to do so, the network monitored annually the mortality and growth of standardized batches of 18-month-old oysters. starting in 1995, the monitoring of the rearing performance of 6-month-old oyster spat was integrated into this network. these sentinel batches were distributed simultaneously each year on 43 sites and were monitored quarterly. these sites were distributed over the main french oyster farming areas and allowed a national coverage of the multiannual evolution of oyster farming performances. most of the sites were located on the foreshore at comparable levels of immersion. field studies were carried out by the "laboratoires environnement ressources" (ler) for the sites included in their geographical area of investigation.following the increase in spat mortality in 2008, the network evolved in 2009 (under the acronym resco). from this date, the network selected 13 sites among the 43 sites previously monitored in order to increase the frequency of visits (twice a month) and the number of sentinel batches. more precisely, sentinel batches of oysters corresponding to different origins (wild or hatchery, diploid or triploid) and to two rearing age classes (spat or 18-month-old adults) were selected. the monitoring of environmental variables (temperature, salinity) associated with the 13 sites was also implemented. the actions of the network have thus contributed to disentangle the biotic and abiotic parameters involved in mortality phenomena, taking into account the different compartments (environment / host / infectious agents) likely to interact with the evolution of oyster rearing performance.finally, since 2015, the network has merged the resco and velyger networks to adopt the acronym ecoscopa. the general objective of this current network is to analyze the causes of spatio-temporal variability of the main life traits (larval stage - recruitment - reproduction - growth - survival - cytogenetic abnormalities) of the cupped oyster in france and to follow their evolution on the long term in the context of climate change. to do this, the network proposes a regular spatio-temporal monitoring of the major proxies of the life cycle of the oyster, organized in three major thematic groups: (1) proxies related to growth, physiological tolerance and survival of experimental sentinel populations over 3 age classes: (2) proxies related to reproduction, larval phase and recruitment of the species throughout its natural range in france, and: (3) proxies related to environmental parameters essential to the species (weather conditions, temperature, salinity, ph, turbidity, chlorophyll a and phytoplankton) at daily or sub-hourly frequencies. working in a geographical network associating several laboratories, ecoscopa provide these monitoring within 8 sites selected among the previous ones to ensure the continuity of the data acquisition. today, these 8 sites are considered as ecosystems of common interest, contrasted, namely : the thau lagoon the arcachon basin the marennes oléron basin the bourgneuf bay the bay of vilaine the bay of brest the bay of mont saint michel the bay of veysthe ecoscopa network is therefore one of the relevant monitoring tools on a national scale, allowing to objectively measure through different proxies the general state of health of cultivated and wild oyster populations, and this for the different sensitive phases of their life cycle. this network aims at allowing a better evaluation, on the long term, of the biological risks incurred by the sector but also by the ecosystems, in particular under the increasing constraint of climatic and anthropic changes.figure : sites monitored by the ecoscopa network

自1993年至2009年，法国海洋研究院（简称IFREMER）启动了该网络项目（简称REMORA），旨在国家层面上研究太平洋牡蛎（Crassostrea gigas）的养殖性能。为此，该网络每年监测标准化的18个月大牡蛎批次死亡率及生长情况。自1995年起，该网络将6个月大的牡蛎苗的养殖性能监测纳入其中。这些哨兵批次每年在43个站点同时分布，并每季度进行监测。这些站点遍布法国主要牡蛎养殖区，实现了对多年牡蛎养殖性能演变的全国性覆盖。大部分站点位于海岸线上，沉浸程度相当。由“环境资源实验室”（LER）对研究区域内站点进行实地研究。2008年苗种死亡率上升后，该网络于2009年（简称RESCO）进行了演变。从那时起，网络从之前监测的43个站点中选择了13个，以提高访问频率（每月两次）和哨兵批次数量。具体而言，选择了不同来源（野生或养殖，二倍体或三倍体）和两个养殖年龄类别（苗种或18个月大的成体）的牡蛎哨兵批次。同时，对与13个站点相关的环境变量（温度、盐度）进行了监测。因此，该网络的行为有助于解开生物和非生物参数，考虑了可能与环境养殖性能演变相互作用的各个部分（环境/宿主/病原体）。最后，自2015年起，该网络将RESCO和VELYGER网络合并，采用ECOSCOPA作为新简称。当前网络的总目标是分析法国凹缘牡蛎（Cupped oyster）主要生命特征（幼虫阶段-补充-繁殖-生长-存活-染色体异常）的时空变异性，并在气候变化背景下长期跟踪其演变。为此，网络提议对牡蛎生命周期的主要指标进行定期的时空监测，这些指标组织在三个主要主题组中：（1）与实验哨兵种群3个年龄组生长、生理耐受性和存活相关的指标；（2）与物种在其法国自然分布范围内的繁殖、幼虫阶段和补充相关的指标；（3）与物种生存至关重要的环境参数（天气条件、温度、盐度、pH值、浑浊度、叶绿素a和浮游植物）在每日或亚小时频率下的指标。在由多个实验室组成的地理网络中工作，ECOSCOPA在这些之前选择的站点中提供了这些监测，以确保数据采集的连续性。目前，这8个站点被视为具有共同利益的生态系统，具有对比性，即：图卢兹泻湖、阿卡松盆地、马雷内-奥利龙盆地、布尔尼夫湾、维莱恩湾、布勒斯特湾、蒙圣米歇尔湾、韦斯特湾。因此，ECOSCOPA网络是国家尺度上的一项重要监测工具，通过不同的指标客观测量养殖和野生牡蛎种群的健康状况，并在其生命周期的不同敏感阶段进行测量。该网络旨在长期更好地评估行业及其生态系统所承担的生物风险，特别是在气候和人为变化不断增加的压力下。图：ECOSCOPA网络监测的站点